It was a dark night on the eve of the German chancellor’s visit to the UK prime minister. In a secure hangar at Berlin’s Tegel Airport, a burly man wearing the uniform of a captain in a Luftwaffe engineering squadron flashed his security pass at the guard on duty. He was waved in out of the heavy rain. Inside the hangar, he took off and shook his wet overcoat before hanging it up on a hook by the door. He walked over to a group of mechanics inside who were busy pre-flighting the gleaming white, four-engine airliner, the surfaces reflected the bright, sodium flood lamps overhead. They greeted him with respect, for he was a hard man and their boss. He checked with a short, tubby sergeant in charge of the team that there were no problems and the work was proceeding on schedule.
Satisfied, the captain noted the positions of where the men were working, strode over to some mobile steps standing against a wall and pushed them towards the outboard engine pod under the port wing. Taking a screwdriver from the pocket of his overalls, he unlatched a small inspection hatch on the side of the engine nacelle and peered inside. Checking over his shoulder and satisfied that everyone else was occupied with their work, he took a small black box out of another pocket, removed a plastic cover strip and attached the box with the exposed adhesive to the inside of the engine nacelle. Checking again that he was not being observed, he reached back inside and flicked a small switch, arming the device. Closing the panel, he locked the latch and climbed back down the steps. Placing them back next to the wall, he walked around the aircraft, returned the tubby sergeant’s salute, put on his overcoat and went back out into the night.